Power-lift tractor hitch for earth working implements



Dec. 22, 1953 H. B. RAPP ETAL POWER LIFT TRACTOR HITCH FOR EARTH WORKINGIMPLEMENTS 4 Sheets-Sheet l Filed Dec. ll, 1946 .7 W gl T l.

vili rllld Dec. 22, 1953 H. B. RAPP ETAL 2,663,239

POWER LIFT TRACTOR HITCH FOR EARTH WOKING IMPLEMEN'ITS 4 Sheets-Sheet 2Filed Dec. 11, 1946 my mi; 57%

Vm PH Nffc owy 2% WY. H5

Dec. Z2, 1953 H. B. RAPP ETAL 2,563,239

POWER .LIFT TRACTOR HITCH FOR EARTH WORKING IMPLEMENTS Filed Dec. 11.1946 4 Sheets-Sheet 3 fill/11,111,114

5,5 f BY /Q. 02%:

Dec. 22, 1953 H. B. RAPP ETAL 2,663,239

POWER LIFT TRACTOR HITCH FOR EARTH WORKING IMPLEMENTS Filed Dec. l1,1946 4 Sheets-Sheet 4 Patented Dec. 22, 19153 vPG'W'ER-I-III:TRACTORHI'IzGlLI-.FOR EARTH .WORKING IMPLEMENTS 'll-iovvard. Rapp, SantaAna,fandLoyd-E. Heckathorn, :Garden Grove, .Calif., assignors :tov'.iownerfManufacturing Co.,. .SantaAna,-;Calif.,

a partnership ApplicationDeceniber 11, 1946; SeriaTNo -'715,"450l 8'-C1ainz1's. 1. (C1. Ste-46.07)

"'Our invention relates vto structures fior pulling and for regulatingthe penetration oteartheworking implements into the soil andfor-otherwise controlling their position during-useior-tr-ansport byautomotive tractors.

A particular object of the invention isftofprovide hitch meansv andregulatingmeans tolbe used-vin conjunction*'therewith which williprovide for ready adaptation of a tractor having autematic power-liftmechanism to thelhandlinga of implements oi varying overhangingweights,that is, of variable Weights disposed at the rearfof thetraetor behindthe-automatic lifting mechanism. Disc harrowsmaybe considered as-'eX-amples of the earth-working tools, -andautomatic power-lift devices areArepresented byithose knownn the' trade as Ford-Ferguson :tractors andgenerally disclosed' inthe- 'Ferguson- Patents Nos. 2,118,180and'2*,ll8,l81. Such-devices and implements are used herein forthepurpose'of illustration; but'it Will'be apparent that"thein vention maybe employed in connection With other implements `and devices. Implementswhich are inherently heavy, such as Ilarge disc harrows of theV `offsettype, vfare 'particularly adapted to use with the' presentmventionfasare implements that `are 'heavy'L whenlo'aded, such as bucket"scrapers'iand' similar structures.

Heretofore, control' deviceshave beenemployed upon tractors for the'purposeV of automatically controlling the depth 'ocut of'earth workingimplements dravvn by the tractors, and alsofor the purpose ofelevatingsuch implements to' an inoperative position'for transportation."'ng'eneral, such devices. have been' thoroughly satisfactory only whenrelatively light implements, suoh'as plov/s, cultivators, and smallvnarrows, have been used with them. However,when heavy implements,suchas the large disc'harrows'an'd the like above indicated, have beenemployed, the automatic controlling devicesy haveA not been entirelysatisfactorybecause of the inadaptability ofthe control devices to careforsuch vcomparatively heavy Weights. VYet, to in'suref'desirablepenetration of the discs of a-disc'harrow' into the soil, the harrowshould beofsubstantial Weight. Consequently, it' vis desirable toA.provide controls and hitch connections which vwill handle bothnlight-Weight implements Iand'r heavy 54implements. v

t is thereforea particular objectief our present inventionV to provide ahitch connectionfor tractors having automatic power-lifts :Which-Willadaptsuch power-lifts to the handling of v'irri-'pflements'of'substantial Weight .astri/veltA- as vimplements ofirelatively.ylightweightk f lt is af further:.object'of'thisj inventionv to iprovidea hitch structure for connecting earth workingimplements,` such-asdisc-harrowato tractors having automaticlpower-lift .mechanisms so thatmost favorable lleverages may be employed .in conjunction ywith such.automatic power-lift mechanisms to enable them to handlelandrcontrolfthe.earth=Workinglimplements in a proper and--satisfactorymanner. .Thisnobj ect. extends bothlfto the' handling-and control ofsuch' implementsfcluring earth working. operations,V Vand` totheir-elevation AvintoY inoperative position for? the purpose i #oftransport.

Anotheri important object -oif the inventionis to? provide in:ysuch-1a-tractor` hitchfl means which Willftransmit a portion of theWeight offlthe implement'directly -to the framework oithetractor;sof-that -onlyf-a portion Aof such Weightisrequired tof-loev liftedbylthe: power-liftmechanism, the-d-raft reaction ofi'thedrawn implementbeing, however, directly applied to `the-automatic powerliftf mechanismA-fore automatic lifting and lowering" o'f the @implementinaccordance-With draft effects.

ltv is' also `arnobje'ct iof-theinvention toA provide a device? havingthe stated lcharacteristics' which isff-useful'l-to:/accomygilisl'l thestated pur-poses,` regardless of Whether the implement'iscom-parativelyJ light-weight orlis relatively 1mueh heavier.

=It-is:affurther object -oi` the invention tovprovide-al hitch toibefused with: heavy implements and in VAcor'rjunction -With automaticpower-'lifts on tractors' gWhich- -Willl -under normal operatingconditions support `a substantial vproportion` of the*Weight-pfv theirmalement directly upon. the tractor, 'draft-reaction torces which'tendf-to produce a I' forward thrust'lduring; operation of 4theimplement,` asfbyelevationtof ya portion' of the implementloyf-t-l1ecearth -uponv/hich it operates, servingito-actuate the controls of theautomatic power-lift so`- thatrthel latter" will-"su'nciently lifttheimplement'to'relieve undue strains and power requirements ofthe.tractor'due to resistance to forward movement. f

Other objects-.and aspects of the invention will become.apparent-tothose skilled in the art .upon reference. to the.accompanyingr drawings andthe followir-ig.- specication vwherein.certain embodiments ,y are-disclosed by VWay ofv illustration.

., Inv the fdrawings,

f`rig..1l is .affside; elevationnof -.a.:hitch of 'this invention shownin operative relation With-a heavy 'disci-harrow and va tractorprovidedv with the :previouslymentioned type --of automatic power-liftEmechan-ism, r#thehitch and harrow being shown by broken lines in alowered, operative position;

Fig. 2 is a fragmentary perspective of the combination shown in Fig. 1,and illustrates principally the hitch mechanism itself;

Fig. 3 is a rear elevation of the hitch mechanism, parts being shown insection, this View being indicated by the line 3--3 of Fig. 1;

Fig. 4 is a fragmentary plan of the hitch mechanism shown in theperspective view of Fig. 2, and indicated by the line 11-4 of Fig. 1;

Fig. 5 is an enlarged scale view, partly in side elevation and partly invertical section, showing the hitch mechanism and also showing in moreor less detail the previously mentioned Ford- Ferguson type of automaticpower-lift such as illustrated in the listed Ferguson patents;

Fig. 6 is a vertical longitudinal section taken approximately on themedian line of the apparatus, and showing a modified form of hitchmechanism;

Fig. 7 is a partial plan view of the hitch shown in Fig. 6, as indicatedby the line 'iof Fig. 6;

Fig. 8 is a view similar to that of Fig. 6, indieating a still furthermodified form of hitch mechanism;

Fig. 9 is an elevational diagrammatic view, from which a number of theparts are omitted, the purpose of this view being to indicate therelative points of attachment of the present improvement to a tractorupon which it is employed and also to indicate certain relationships inconnection with operational movements; and

Fig. 10 is a detail on an enlarged scale showing a modified form ofmounting for the double A- frame construction of the form of Figs. 1 to5.

Referring to the drawings, and particularly to that form of theinvention which is illustrated in Figs. 1 to 5, there is shown aconventional type of tractor comprising a frame i having a rear axle I2carrying at its opposite ends rear wheels I4. The upper portion of theframe lll constitutes a superstructure which includes a portion i5 uponwhich is normally mounted a conventional seat l' supported by a U-shapedleaf spring Il secured by screws i8 to the top of the superstructureportion i5.

The superstructure portion l5 and the frame lil contain an automaticpower-lift mechanism generally indicated at and shown in considerabledetail in Fig. 5. This automatic power-lift mechanism, which asillustrated is substantially the same as that shown in the abovementioned Ferguson Patents Nos. 2,118,180 and 2,118,181, includes alifting lever 22 having a lower arm 23 disposed within the mentionedsuperstructure, and fixed upon a transverse shaft 2li. bifurcated at itsop-p-osite ends to provide two exposed lifting arms 25. The upper endsof the lifting arms 25 are connected by universal joints 2t withelevating pull rods 2li whose lower ends are pivotally connected at 28to elevator levers 3c. The pull rods 2l in conjunction with the leverarms 25 thus act as elevators for the elevator levers 3B. The elevatorlevers 3B have their forward ends mounted by means of pivots 32 uponadjacent side portions of the tractor frame iii and thereby alsoconstitute draft arms. The elevating mechanism is automatically actuatedby mechanism shown in Fig. 5 and later to be described in connectionwith the functioning of various parts of the hitch.

The rearward ends of the elevator levers Sii are pivotally mounted uponpins 34 which are carried upon the rearward ends of return arms 35 (seeFigs. 2 and 5) whose forward ends are secured upon the outer ends of atransverse draft bar 36. Such forward ends of the return arms 35 areprovided with a pair of outwardly directed, integrally attached liftinglugs 33 between which intermediate portions of the respective elevatorlevers 3d are disposed, these portions of the levers 3E beingimmediately rearward of the pivot points 28 by which the pull rods 2 areattached to the levers Sil. In this manner the lifting eifect producedby the pull rods 2l upon the elevator levers 3S is applied to the draftbar 36 close to the lifting points provided by the pivots 28. Suchpoints of connection, whichv may be at approximately the halfway pointsalong the levers Sil, provide for the disposition of the lifting regionwell forward of the harrow between the rear wheels iii and toward therear axle i2 in the tractor frame lil. inasmuch as the elevator levers3%, the pull rods 21, and the described lifting mechanism including thelifting lever 22 are original equipment on a tractor, the indicatedconstruction of the hitch provides for convenient attachment of thehitch while at the same time bringing the draft bar 36 forward as far aspossible and well beyond the pivot points provided by the pins Thus, thepower required in the power-lift mechanism to lift a given weight isminimized.

Thus far, the structure described for the form of Figs. 1 to 5 in thesame as employed in connection with the forms of Figs. 6 to 8. In theform of Figs. l to 5, the transverse draft bar @t carries a lower andinner framework fifi of a type common in this art and generally referredto Vas an A-frame. The A-frame it in turn carries an upper and outerA-frame 42. Each of the A- fmmes d and l2 comprises a pair of spacedupstanding legs 3 which diverge as they extend downward, the lower endsof the legs i3 of the upper and outer A-frame 42 being pivoted on thelower diverging portions of the legs [i3 of the A- frame 4i) by means ofbolts dit. The pivots provided by the bolts lid thus lie somewhat abovethe pivot points provided for the A-frame d@ by the transverse draft bar3a. The described arrangement of the two A-frames d0 and d2 serves toprovide a two-member framework through the medium of which the movementsof the implement to be drawn are controlled. The lower or cross barportion of the A-frame d'3 is provided by the draft bar 35, and thelower portion of the A-frame i2 is in turn provided by the A- frame ddand the pivot bolts d. The narrower, upper portions ofA each of theA-frames it and :i2 are properly spaced by means of spreaders i5 and 4S,respectively. Above the spreader of the A-frame 42 and between the upperportions of the corresponding legs the rearward end of a rigid top linkor supporting tension link t8 is pivotally mounted upon a pivot pin d3,and above the spreader d5 of the lower A-irame itl a thrust link 5E ispositioned, the thrust link 5d being connected with a heavy spring 52constituting a part of the automatic control of the power-lift nism 20,as later to be described.

The present hitch mechanism is adapted for attachment of implementsconsiderably heavier than those for which the automatic power-liftmechanism 26 was originally designed, as previously indicated. in thepresent instance, a disc harrow 55 is employed for the purpose ofillustration, this harrow comprising any type of harrow frame 5t havinga forward gang of discs 5l and a rearward gang of discs 58 ofconventional type, as best indicated in Fig. 1 where the' of which ahand crank 6d is provided; Thelowerend-fof the sleeve 62 is Amounted lon:a pivot 65 carried in a Vbracket G6 uponthe 4top of a'transverse`middle portion olofjthefharrow frarne'l'.r The upper endof vthe shaftfil-3 is rotatably vse-v cured'in a bearing te mountedupon trunnion 69"between the vupper Yextrenfiities ofA the legs t3 of the upper A-frames2. By actuation of--Ythe crank Sii; the rod structure $0 `may have itslength adjusted'as'required', whereby to elevate the rearward gang ofdiscs 58 yas required with respect to the forwardgang,ofjdiscs'iythecorresponding weight beingtransmittedfto the`framework comprising the A-framesj,1l'and 32' and a portionthereofbeing `transmitted through the rigid top link ditto the superstructureofthe tractoryand particularly to the portion loof-the superstructure.To effect 'this result, the forward end 'of the top link 43 ispivotally'mounted upcna bracket plated@ by apivotpin'll carried betweenears 'l2 on the rearward ven dfof the racket plate it. The bracket"platej 'ED- is lsee cured, as shown, to 'the Vsuperstructure of thevtractor frame i?! through the y'medium ofthe screws i8 by whichthe seat`spring il is attached, this being a convenient method Aof mounting ontractors of this type,jand this mounting servingialso to placethe'attachmentpin 'l'lV forward'of the'axle Yi2 andfforward Aof thepivots 32 for the elevator levers 38. v K

The forward portionof the fra-ine 58 'of the harrow 55 is Aconnected forAdraft through the lower Aeframe 4G by means off-bent, forwardlyextending, rigid draft 'arms l5 lwhose l'rearward ends arewelded to anangleV iron- 'iiiv securedY by bolts ita to an angle ironv Etaivhichconstitutes the forward portion'of'the frame 5t" and-isse cured'to'thesidemembers thereof `as 'by means of appropriatejbrackets 'il'. rlheforward VendsY 'itaA of the bent draft arms 'l5 project'downward and areconnectedbyV means of'pivot bolts'irA to lower dependingends fia'of thelegs-E3 of `the` lower A-frametl. VSince such yend-s lila liebelow thetransverse draft bar 35, the resistance of 'thefharrow *55* to forwardmovement -creates a rearward pullupon the'lower endsl lila of theA-frame d and a consequent forwardV thrust of the upper end of, thelowerA-fframev dil whichv is transmitted tothe thrust 'linkiE 'andjthence totheispring '52 and associated-parts vof the control deviceifortherautomatic power-*lift mechanismV 29;

Between the draft arms T5; a 4bracebar 'itis disposed, the arms 'i5being shown as formed "of" angle material f or additional l brewing andvf or the further purpose oficonstitutinga weight box to receive, aweight upon the horizontal members of the angle material, designatedtl,shouldadditional weightjbe required to effect desired# earth penetrationby the forward harrow discs 5-l.

Further bracingofkdraftsarms T51 is effectedibyangularly f disposed?'brace :rods iii-extending betweenthe angle iron-11oofftheS-harrowlframel 56'- 4outer. A-frame A2 ismounted upon the lowerinner -A-frame 4d, serve` as support Vmeans by which -part v.of therearward weight ofthe harrow- 55--taken through the rod structure-6o istransferred to thel lower A-frame 4i] and 'thence to the-transversedraft bar 36, the lugs 38, and thel elevator levers 39s. The remainderYof 'the rearward Weight of the harrow taken through the rod structure tois transferred through `the` top linlrfll` to the superstructure at thetop fof the tractor frame Illfas previously disclosed. Asthe harrow-y55V is drawn forward by the describedtractor,V the resistance of theharrowto forward movement is transmitted through the draft arms 15-tothe lower ends lilal of thev legs d3 of the- `lower A-frame 49, thelatter vtherefore tending` rframer'and is supported thereby; vAtl thesamer time,the top link d3 resists any tendency of the upper A-'frame 42torock forward'under lthe inuen'ce-of f' any weight carried in theweight-box between the draft arms 75. In this-manner, anyweightl appliedto the forward gangof discs- 57 by way of the weight-box is caused to beproperly applied vwithout interfering with theproper. functioning of anyportionr of the frameworkconstitutedby the double A-frame which theA-frames 40 and 42 form, and-anybuokling that might occur if thetop link43 was flexible is avoided. By the vconstruction disclosed, all of theseparts are located very close to the rear` axle "I2 of. the. tractor andto the usual differential housingv disposed thereabout and carriedatAing points on the elevator levers 3@ are'disposed closely adjacent thedouble ,er-framev and the weights to be lifted. Y

vThe thrust link 5i), by which the resistance to vforward movement iscommunicated through the tcp of the lower A-frame da to thecompressionspring 52 of the control'device for the automatic power liftZ, is telescopic in order to pro vide lfor elevation of the operativeparts into'a transport position higher than the position shown in Fig.1, and corresponding with the broken-line position of the elevatorlevers 3d, ofFig. 5. When in such elevated position, the rearward end ofthe thrust link 5o and the adjacent upper 'end of the A-frame All willassume a sharply elevated position from the full line position of Fig.v5, thereby requiring the considerable extension of some element. This isaccomplished through the medium of an elongated sleeve constitutingtheouter member 'of the thrust link El?, the rearwardA end of the sleeve85 being pivoted through the-medium of a pivot pin 86 upon theupperextremity of the A-frarne EL Within the sleeve 8,5, aslidabletelescoping link member d? is. disposed. The link member 3l is providedwith a lostmotion slot 83 inl which; is :positioned :a transyerse: stoppinin thefprrrl` ofacrossbolt g 89 fixed in the sleeve 85. Uponelevation of the parts into the mentioned transport position, the bolt89 travels into the rearward end of the slot 88, and when the parts arelowered, the bolt 89 travels into the forward portion of the slot 88 asseen in Fig. 5. When the upper end of the A-frame 49 is moved forward bydraft reaction of the draft arm i on the lower end of the A-frame cli,the bolt 39 moves to the forward portion of the slot 88, and therearward extremity of the link member 8l is engaged by the bottom of thesocket of the sleeve 85 to produce the required forward thrust. Suchthrust is transmitted by the link member 8l to a bell crank 9B whoselower end is pivoted at SI upon an adjacent upper rearward corner of thetractor frame I0, this point being normally slightly rearward of theaxle I2 and the pivots 32 for the elevator levers 38, and also beingrearward of the universal joints on the lifting arms 25 and the pivotpin ll by which the top link 4B is connected with the bracket plate 1li.

The thrust from the link member 5! is effected through a pivot pin 92carried by the upper end of the bell crank et, which in turn transmitsthe thrust to a control rod 93 whose outer end in turn is attached tothe `cell crank 90 by a pivot pin 94. The control rod 93 carries acollar d5 bearing against the earlier mentioned compression spring 52,which spring resists the thrust being transmitted through the thrustlink 5S. The opposite end of the spring 52 is disposed around a guidesleeve 9'! through which the control rod Q3 passes to the interior'ofthe tractor frame Iii, the guide sleeve @l having a collar 9S upon whichthe adjacent end of the spring 52 bears, the position of the sleeve 91and its collar 98 being maintained against the adjacent portion i5 ofthe superstructure on the tractor frame iii. Within a cavity within thesuper-structure portion I5, the inner end of the control rod 93 reciprocates, such inner end being connected by a pivot 9% to an adjacentend of a curved control link It@ whose opposite end is connected to amovable pivot it! carried by a control lever iiiZ. The function of theseparts is to control auto- ;atically, under actuation by the control rod93, the passage of hydraulic liquid to the interior of a cylinder idd inwhich a piston I5 reciprocates for the purpose of moving a piston rod|08 connected to the lower end of the arm 23 of the lifting lever 22disposed on the shaft 24 which operates the exposed lifting arms 25,which in turn.

actuate the pull rods 2l and elevator levers 3i) in accordance with theshifting of the movable pivot it! and of the control lever m2 throughthe mer dium of the thrust link 5t. ln this specific construction, whichis substantially that currently employed on standard Ford-Fergusontractors, the control lever it cooperates with an auxiliary lever W8pivoted at iii@ and controlling a valve Hi regulating passage ofhydraulic fluid from a pump H2 to and from the cylinder IM by conventional fluid lines (not shown). in this particular form of liftmechanism a quadrant control lever lid is employed whose upper end ispositioned adjacent the drivers seat along a conventional quadrant H5.The lower end of the quadrant lever i iii is pivoted upon the side ofthe portion Iii of the superstructure and carries an eccentrically thecontrol lever IiiZ, the fulcrum IIS bearing -upon an appropriate face atthe upper end of the lever |32. A spring II'I is attached to a portionof the auxiliary lever bear continuously against a stop H8 on the lowerill and works located fulcrum IIG forv |08 to cause the latter to -Lllend of the control lever IM. This spring serves not only to control thelever IS and the valve i iti, but serves also to force the upper end ofthe control lever l against the movable eccentric fulcrum I itregardless of the position of the movable pivot lili. Thus, when theeccentric fulcrum HE is moved by manual actuation of the quadrant leverH, the control lever It? is correspondingly shifted, and, kewise as themovable pivot Elli is shifted through movement of the thrust link 5t,the control rod 13 and the curved control link it', the lower end of thecontrol lever HG2 and the stop I it are correspondingly shifted. In thismanner the valve il@ is actuated automatically to cause the liftinglever 22 and its lifting arms 25 to operate automatically in accordancewith draft reactions of the harrow (or other implement being drawn), andalso in accordance with the desires of the tractor driver in the seatl5. While the Ford-Ferguson type of automatic power-lift mechanism ishere described for the purposes of completeness, it is apparent that anyother specic control and actuating means may be operated through themedium of the control rod $3 Working against the compression spring 52to eect the required movement of the lifting arms 25.

To summarize the operation of the entire strucu ture disclosed in Figs.l tc 5, resistance to the forward draft movement in the earth, developedby the harrow 55, is transmitted through the draft arms 'f5 to the lowerextremities lila of the legs li of the lower A-frame im, therebyproducing a corresponding thrust upon the thrust link 5t, which thrustis transmitted through the control rod t3 against the strong compressionspring 5E to effect automatic actuation as just described above. Theoverhanging weight of the rear por tion of the harrow 55, which istransmitted through the adjustable rod structure Gil to the top of theupper A-frame i2 by way of the bearing IES and trunnion 5%, is partiallytransferred to the super-structure of the tractor frame It by means ofthe rigid connecting link dii attached to the upper end of the upperA-frame 132 and to the bracket plate l@ carried by the aforesaidsuperstructure of the tractor. This link d8 also resists any jackkniflngor buckling tendencies and maintains the upper A-frame i2 substantiallyin a constant relationship to the tractor frame for any given positionof elevation of the parts. The required proportioning of the harrowweight transmitted to the earth through the respective forward gang ofdiscs 5l and rearward gang of discs 58 is accomplished by the tractordriver from his seat i6 through the hand crank et which extends orshortens the rod structure Bil as desired. Proper proportioning of theweight in this manner regulates the draft effects on the two disc gangsso that all tendency toward side draft is eliminated.

Thus, when draft reactions of the harrow 55, created by resistance toforward movement, are suflicient to cause the draft arms 'i5 to swingthe lower A-frame d about the draft bar tt and in turn cause the thrustlink 5t and control rod 93 to compress the control spring 52, hydraulicfluid is passed to the cylinder Idil by the valve l iii to actuate thepiston i5 and cause a corresponding lifting effect to be transmitted tothe elevator levers 3i! by the lifting arms 25 and the pull rods 21.Such actuation results in partial elevation of the harrow 55, theelevation becoming greater as the resistance to forward draft increases.Since a substantial proportion of the weight of the purpose, and cuttingsuch socket portion down to that length. VIn this manner, the mentionedentre. weight of the given implement is offset, and the lift mechanismcorrespondingly relieved. If an implement of different weight issubsequently used, the set of the spring |44 is changed by changing thenut |45, or both the spring MG and the nut |45. Thus, the compressionspring 52 responds more readily to the draft reactions of the implementas transmitted through the thrust link :3G and the control rod 93.

In the construction shown in Fig. 8, as well as that of Fig. 6, thedraft arms 15 being carried directly upon the transverse draft bar 36,the draft reactions from the narrow or other implement are transmittedthrough the adjustable rod structure te, the bearing 5B, the top link|23 and thrust link |30, without reliance upon draft applied to anextending lower portion of the A-frame |25.

In each of the three forms above described, the pulling points for theimplement from the tractor are the pins provided at the rearward ends ofthe return arms 35 where the rearward ends of the elevator levers 3o areattached. Also in each forni, the balancing of the weight of the harrow55 for proper disposition of such weight upon the forward gang of discsi and upon the rearward gang of discs 58, in order to effect de siredearth'penetration and eliminate side draft, is accomplished through thenecessaryr lengthening and shortening of the rod structure Si) by meansof the hand crank iis on the threaded shaft es. Again, in connectionwith each form, when the harrow 55, or other implement, developsundesirable resistance to forward movement, the apparatus works incompression, that is, causes compression of the spring 52 if the controlrod et is forced inward to aotuate the control lever m2 to effectlifting operation of the piston It. As above indicated, such operationin compression is eected in the forms of Figs. l to 5 through draft ofthe draft arms 'i5 upon the extensions of the A-frame 4i) where thepivot bolts 'i8 connect the draft arms i5 thereto, the correspondingthrust being imparted through the telescopic thrust link 53. In theforms of Fiss. 6 to 8, wherein the draft arms 'i5 are attached to thetransverse draft bar 35, operation by compression is effected solelythrough the adjustable rod structure and thence to the top link |28 andthe thrust link i3d. In these forms, operation by compression, whenrequired, is assisted by the compensating spring |45. to the extent thatthe rearward weight of the implement, that is the Weight which we havetermed overhanging weight, is carried by the portion l5 of the tractor'superstructure. When the weight of the harrow or other implement, isproperly irnposed upon the soil being cultivated, the elevator leversSi? being lowered accordingly, as in the broken line position of Fig. 1,the apparatus is considered as working in tension, the control rod 93being pulled out to permit expansion of the compression spring 52, suchweight disposition being permitted by proper adjustment of theadjustable rod structure Ell. In view of the relative angularity of thetop links 43 and |28 of the various forms with respect to the elevatorlevers Sil, lowering of the implement tends further toward suchoperation in tension by reason of the effective lengthening of the toplinks 48, 2Q, which constitute supporting links, this effect continuinguntil such time as increased mit resistance in the rearward portion ofthe irnplement tends to cause a buckling through the rod structure tewith consequent reversal to operation in compression through the thrustlink 5S of the forni of Figs. l to 5 and through the top link itil andthrust link of the other forms.

In the forms of Figs. 6 and 8, operation in compression is assured byreason of the lost motion connection provided by the hooks |32 in whichthe cross pins of the thrust links i353 slide.

In Fig. 9 there is shown somewhat diagrammatically the relationship ofthe various Vparts of the present hitch to one another and to thetractor to which the device is attached, certain relationships inconjunction with the movements being indicated in broken lines. In thisfigure, the double A-frarne structure provided by the lower A-frame sand the upper [Mrame .2 of the form of Figs. 1 to 5 is employed,although, in generaLvthe same relationships exist where the singleA-frame |25 of the forms of Figs. 6 and 8 is employed. As seen, thepivots 32 for the elevator levers Sii are disposed below the tractoraxle i2, and also are desirably disposed slightly forward with respectto such axle. The pivot Vpin 'il carried by the bracket plate 'io bywhich the forward end of the rigid top link i8 is attached to thetractor is not only well elevated above the axle l2 and thereby wellspaced vertically from the pivots but is also disposed forward of theaxle i2, the pivots 32 and the pivot @l for the bell crank Se.

Thus, a rough parallelogram of forces is provided by the pivots 32, thepivot pin 'i i, the pivot pin 49 by which the rearward end of the toplink 48 is attached to the upper portion of the upper A-frame d2, andthe effective points of connection of the draft ybar 36 to the elevatorlevers 39 which are provided by the lugs Se. Since the pivot points 2Sby which the pull rods 21 are attached to the elevator levers 3@ arelocated closely adjacent the lifting points provided by the lugs 38,effective leverage to elevate the mechanism is accomplished. Also suchdisposition of the lifting points provided by the lugs 3B insuresattachment of the draft mechanism for the harrow, or other implement, asfar forward toward the tractor axle l2 as is possible.

As will be observed from Fig. 9, as well as from Fig. 5, the rigid toplink [i3 when in ordinary operating position is angled upward as itextends rearward, being thereby somewhat out of parallelism with thelifting levers 35i. As a result, when the double A-frame is bodilylifted, the pivot pin de swings about the pivot 'ii as a center todescribe a short aro forward as indicated by the curved arrow iet. Thishas the effect of swinging the top of the upper A-frame d?. sornes whatforward as the lower A-frarne lo is elevated, thereby causing theadjustable rod structure |50, through its attaching pivot 55 to lift therearward portion of the harrow 55 at a faster rate than the forwardportion and into such an angled position as indicated by the brokenlines. This lifting of the rearward portion of the harrow and its reargang of discs 5S to a greater elevation than the forward portion of theharrow and its forward gang of discs 5I has considerable advantage forthe purpose of transport. This advantage is due to the fact that, as thetractor moves over rough ground, the overhanging rear gang of discs 5chas greater freedom of movement without striking the earth or 4Vroadway.Since lthe -pointr of attachment: Vfor the A forward4 end of'ftne toplinkse, providedfby the pivotpinrllf, is placedwellrforward on, thetractor towardthe center of gravity thereof and forward ofthetractoraxle t2, thegoverhanging weight of the rear portion of thearrowiseii. ciently transferred to the: tractor itself and thence to thetractor-wheels.`

As illustrated in Fig. 10, the mounting of the upperV A-frame 42 withrespect to the lower A-frame lie may be accomplished by pivoting thelower. ends of its legs 43 directly upon the transverse draftbar 36,insteadof mounting it upon theI lower A-frame by meansiofthe pivot boltsidiof the form of Figs. 1 to 5.

In connection with the constructiomshown, it isto be nOted that meansare providedto facili tate retention of the parts4 inassembledrelationship when necessary tolchange implements. Thus, theforward angle iron l'i, which maybe adaptedfor attachment to varioustypesof implements, may be disconnected from the-forward portion of theharrow frame Etf as by theremoval of the bolts '15a (Fig. 2). When thishas been done, the tendency of the draft arms l5 y and the weight boxprovided therein is to swing downward. The amount of this swingingmovement is limited by rearwardly extending lugs |15, Fig. 5, which arecarried on the rearward edges of the lower ends fwd of the legs f thelower A-frame im, these lugs H lying in the path of the draft arms 'l5when they begin to swing downward. Similarly, the cross bolt 89 in thethrust link prevents the sleeve member 85 from being disconnected fromthe link member 8l.

Other variations of the generic invention here disclosed will becomeapparent to those skilled in this art, and we therefore intend toprotect all modifications which fall within the scope of the claims.

We claim as our invention:

1. In combination in a hitch structure for connecting a drawn implementframe to a tractor having a superstructure and having elevating means toraise and lower the drawn implement frame, power-lift mechanismconnected with said elevating means, automatic control means for thepower-lift, and draft arms connested to a lower portion of said tractorand to said elevating means for lifting said implement frame throughsaid draft arms, the combination including: an upstanding rigid frame;means connecting a lower portion of said frame with said draft arms forelevation thereby; link means connecting an upper portion of theupstanding frame with a rearward portion of said implement frame, andlink means connecting an upper portion. of said upstanding frame with arigid location on said tractor superstructure above said draft arms totransfer a portion of the weight and strain of the rear of saidimplement frame to the upper portion of said tractor through saidupstanding frame and said rigidl location; a second opstanding rigidframe; means connecting said second frame with said draft arms forsupport thereon; means pivotally connecting the lower portion of saidsecond frame to a forward portion of the implement frame fc support ofthe latter on said second frame; and a thrust link pivotally connectedwith an upper portion of said second upstanding frame and connected withsaid automatic control means to control said power-lift mechanism andlift said draft arms.

2;- ammirati/ion as; claim; y1 wherein. the iowerpart of; the, rstmentioned @Standing rrameiisnivoted on the. seondupstandine frame 3'. Acombina-tion as in claim 2 wherein the connectionl of said second.framev with said draft arms includesa pivotal connection.`

4: A combination as `in claim l wherein said connection of saidsecondframe includes a pivotal connection.

5; A combination as in `claim l wherein the forward end ofvsaidlimplement frame is pivotally connectedv tothe lower portion ofvsaid second upstanding fra-me, and an intermediate portion of'saidSecond; frame is provided with a cross shaft; providing.f or theconnection of said second frame with `said draft-arma the ends of saidcross shaft vhavin-g thereon Y jawy means which engagewith the upper andlow-er edge portions of intermediate parts of said draft arms, and shortarmscarrying-said jaw means and extending rearwardly and' connected tothe rearward ends of'said draft arms whereby said draft'arms pull saidimplement frame through said short rms, saidcrossshaft.- and said secondupstanding frame.

5. in combination in a hitch structure for connecting a drawn implementfran e to a tractor having a super-structure and having elevating meansto raise and lower the drawn implement frame, and also having power-liftmechanism connected with said elevating means, automatic control meansfor the power lift, and draft arms connected to a lower portion of saidtractor and to said elevating means for lifting said imp1ement framethrough said draft arms, the combination including: an upstanding rigidframe whose lower portion is connected with said draft arms forelevation thereby; link means connected to and leading upward from aportion of said implement frame to and directly connected with an upperportion of said-upstanding rigid frame for supporting weight of saidimplement frame and its implement from the upper portion of saidupstanding rigid frame; a tension link connecting an upper portion ofsaid upstanding frame with a rigid location on said tractorsuperstructure above said draft arms to transfer strain of said weightof said implement frame and its implement to the upper portion of saidtractor through said opstanding frame and said rigid location; a second.opstanding rigid frame connected with the first upstanding rigid frameand also supported by said draft arms for elevation thereby; meansrigidly connected with said implement frame and pivotally connectingsaid implement frame with said second upstand ing rigid frame forsupport of said implement frame on said second frame; and thrust linkmeans pivotally connected with an upper portion of said secondopstanding frame and also oonnected with said automatic control means tocontrol said power-lift mechanism for lifting said draft arms and saidupstanding rigid frames.

7. A combination as in claim 6 wherein said thrust link means includes alost-motion connection permittingelongation upon elevation of saidupstanding frame.

8. In combination in a hitch structure for connecting a drawn implementframe to a tractor having a superstructure and having elevating means toraise and lower the drawn implement frame, power-lift mechanismconnected with said elevating means, automatic control means for thepower-lift, and draft arms connected to a lower portion of said tractorand to said elevating means for lifting said implement frame throughsaid draft arms, the combination including: arm means rigidly attachedto said implement frame to support the implement; thrust link meansconnected with said automatic control means to control said power-liftmechanism and lift said draft arms; a first upstanding rigid framehaving a portion pivotally connected directly to said thrust link means,said implement-supporting arm means being pivotally connected directlyon said upstanding rigid frame for support of said implement on saidupstanding rigid frame; a second upstanding rigid frame pivotallyconnected with the iirst upstanding rigid frame and thereby havingsupporting connection with said draft arms; second link means connectingthe upper portion o said second upstanding rigid frame with a rigidlocation on said tractor superstructure above said draft arms totransfer Weight strain of said implement frame and its implement to theupper portion of said tractor through said second frame and said rigidlocation when said rigid frames and implement frame are elevated by saidpower lift, said elevating means and said draft arms; and meansinterconnecting an upper portion of said second upstanding rigid frameand said implement frame for lifting said implement frame with saidupstanding frames by said elevating means and said draft arms throughsaid interconnecting means.

HOWARD B. RAPP.

LOYD E. HECKATHORN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,077,942 Lindgren Apr. 20, 1937 2,159,669 Morkoski May 23,1939 2,312,258 Martin Feb. 23, 1943 2,322,342 Bunn June 22, 19432,337,801 Cook Dee. 28, 1943 2,349,257 Evans et al May 23, 19442,398,147 McKay Apr. 9, 1946 2,414,114 Martin Jan. 14, 1947 2,441,630Heitshu May 18, 1948 2,456,693 Fraga Dec. Z1, 1948 2,575,622 Fraga Nov.20, 1951

